Various novel bicyclo[3.3.1.]nonenol derivatives were synthesized in an efficient one-pot procedure in a remarkably stereoselective reaction. The title compounds show significant antitumor activity against human cancer cell lines. A variety of cinnamic acid derivatives were linked to the title compounds as side chains in order to enhance the antitumor activity. These compounds were subjected to the in vitro antitumor screening, and the results are discussed. It seems important with respect to antitumor activity to locate an aromatic ring at the C-7 position of the bicyclo[3.3.1]nonane framework.